<h2>DESCRIPTION</h2>

This command has 2 modes of operation. If no <b>date</b> argument is
supplied, then the current timestamp for the raster map is printed. If
a date argument is specified, then the timestamp for the raster map is
set to the specified date(s). See examples below.

<h2>NOTES</h2>

Strings containing spaces should be quoted. For specifying a range of
time, the two timestamps should be separated by a forward slash. To
remove the timestamp from a raster map, use <b>date=none</b>.

<h2>TIMESTAMP FORMAT</h2>

The timestamp values must use the format as described in the <em>GRASS
Datetime Library</em>. The source tree for this library should have a
description of the format. For convenience, the formats are reproduced
here:

<p>There are two types of datetime values:

<ul>
  <li><em>absolute</em> and
  <li><em>relative</em>.
</ul>

Absolute values specify exact dates and/or times. Relative values
specify a span of time. 

<h3>Absolute</h3>

The general format for absolute values is:

<div class="code"><pre>
  day month year [bc] hour:minute:seconds timezone

	     day is 1-31
	     month is jan,feb,...,dec
	     year is 4 digit year
	     [bc] if present, indicates dates is BC
	     hour is 0-23 (24 hour clock)
	     minute is 0-59
	     second is 0-59.9999 (fractions of second allowed)
	     timezone is +hhmm or -hhmm (eg, -0600)
</pre></div>

Some parts can be missing, for example

<div class="code"><pre>
	     1994 [bc]
	     Jan 1994 [bc]
	     15 jan 1000 [bc]
	     15 jan 1994 [bc] 10 [+0000]
	     15 jan 1994 [bc] 10:00 [+0100]
	     15 jan 1994 [bc] 10:00:23.34 [-0500]
</pre></div>

<h3>Relative</h3>

There are two types of relative datetime values, year-month and
day-second. The formats are:

<div class="code"><pre>
	     [-] # years # months
	     [-] # days # hours # minutes # seconds
</pre></div>

The words years, months, days, hours, minutes, seconds are literal
words, and the # are the numeric values. Examples:

<div class="code"><pre>
	     2 years
	     5 months
	     2 years 5 months
	     100 days
	     15 hours 25 minutes 35.34 seconds
	     100 days 25 minutes
	     1000 hours 35.34 seconds
</pre></div>

The following are <i>illegal</i> because it mixes year-month and
day-second (because the number of days in a month or in a year vary):

<div class="code"><pre>
	     3 months 15 days
	     3 years 10 days
</pre></div>

<h2>EXAMPLES</h2>

Prints the timestamp for the "soils" raster map. If there is no
timestamp for "soils", nothing is printed. If there is a timestamp,
one or two time strings are printed, depending on if the timestamp for
the map consists of a single date or two dates (ie start and end
dates).

<div class="code"><pre>
r.timestamp map=soils
</pre></div>

Sets the timestamp for "soils" to the single date "15 sep 1987".

<div class="code"><pre>
r.timestamp map=soils date='15 sep 1987'
</pre></div>

Sets the timestamp for "soils" to have the start date "15 sep 1987"
and the end date "20 feb 1988".

<div class="code"><pre>
r.timestamp map=soils date='15 sep 1987/20 feb 1988'
</pre></div>

Sets the timestamp for "soils" to have the start date "18 feb 2005
10:30:00" and the end date "20 jul 2007 20:30:00".

<div class="code"><pre>
r.timestamp map=soils date='18 feb 2005 10:30:00/20 jul 2007 20:30:00'
</pre></div>

Removes the timestamp for the "soils" raster map.

<div class="code"><pre>
r.timestamp map=soils date=none
</pre></div>

<h2>KNOWN ISSUES</h2>

Spaces in the timestamp value are required.

<h2>SEE ALSO</h2>

<em>
  <a href="r.info.html">r.info</a>,
  <a href="r3.timestamp.html">r3.timestamp</a>,
  <a href="v.timestamp.html">v.timestamp</a>
</em>

<h2>AUTHOR</h2>

Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

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